JP2017214534A - Rubber composition and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire rubber composition that achieves improvements in wet grip performance and wear resistance as well as fuel consumption, and a tire tread and a tire prepared therewith.SOLUTION: A rubber composition contains raw material chemicals that contain a rubber component containing styrene-butadiene rubber, a filler containing silica with a CTAB specific surface of 100 m/g or more and a BET specific surface by nitrogen adsorption of 110 m/g or more, a silane coupling agent, and an aluminum organic compound.SELECTED DRAWING: None

Description

  The present invention relates to a rubber composition, in particular, a tire rubber composition, and a tire tread and a tire produced using the rubber composition.

  The tire is composed of various members such as a tread and an inner liner, and various performances are imparted to each member. The tread that contacts the road surface is required to have wet grip performance from the viewpoint of safety and the like, and a method for improving the performance by adding aluminum hydroxide has been proposed (Patent Document 1).

  However, when aluminum hydroxide is added, there is a problem that the fracture strength is lowered and the wear resistance is deteriorated, and further improvement is demanded.

JP 2002-338750 A

  The present invention relates to a rubber composition, and in particular, a rubber composition for a tire having improved rubber breaking strength, wet grip performance and wear resistance, and improved fuel efficiency characteristics, and a tire tread made using the rubber composition And trying to provide tires.

  As a result of intensive studies to solve the above problems, the present inventor blended a predetermined rubber component with a filler containing a predetermined silica and a silane coupling agent, and further replaced with a predetermined amount of aluminum hydroxide. It discovered that the said subject could be solved by mix | blending an aluminum organic compound, repeated examination, and completed this invention.

That is, the present invention
[1] A rubber component containing styrene butadiene rubber, a filler containing silica having a CTAB specific surface area of 100 m ² / g or more and a BET specific surface area of 110 m ² / g or more by nitrogen adsorption, a silane coupling agent, and an aluminum organic compound A rubber composition comprising raw material chemicals,
[2] The rubber composition according to the above [1], wherein the filler further contains carbon black,
[3] The amount of silica is 50 to 150 parts by weight, preferably 60 to 120 parts by weight, more preferably 60 to 110 parts by weight, and the amount of carbon black is 5 to 50 parts by weight with respect to 100 parts by weight of the rubber component. Preferably it is 5-35 mass parts, More preferably, it is 5-20 mass parts, More preferably, it is 8-20 mass parts, The compounding quantity of an aluminum organic compound is 5-45 mass parts, Preferably it is 5-40 mass parts, More preferably, it is. 7-40 mass parts, More preferably, it is 10-40 mass parts, Comprising: The compounding quantity of a silane coupling agent is 1-20 mass parts with respect to 100 mass parts of silica, Preferably it is 1.5-20 mass parts. The rubber composition according to the above [2], preferably 2 to 20 parts by mass, more preferably 5 to 20 parts by mass, further preferably 5 to 15 parts by mass, and further preferably 7 to 12 parts by mass. ,
[4] The rubber composition according to any one of claims 1 to 3, wherein the CTAB specific surface area of silica is 180 m ² / g or more and the BET specific surface area by nitrogen adsorption is 185 m ² / g or more.
[5] The aluminum organic compound has the formula (1):
Al (OR ^a ) (OR ^b ) (OR ^c ) ₃ (1)
(In the formula, R ^a , R ^b and R ^c each independently represents an aliphatic hydrocarbon group.)
The rubber composition according to any one of [1] to [4] above, which is an aluminum alkoxide represented by:
[6] A tire tread produced using the rubber composition according to any one of [1] to [5] above,
[7] A tire having the tire tread of [6] above,
About.

  According to the present invention, a rubber composition having excellent properties, in particular, a rubber composition for tires that has improved rubber breaking strength, wet grip performance and wear resistance, and also improved fuel economy characteristics, and A tire tread and a tire manufactured using the tire can be provided.

  Hereinafter, modes for carrying out the invention will be described.

<Rubber component>
The rubber component includes styrene butadiene rubber (SBR). SBR is not particularly limited, and examples thereof include emulsion polymerized styrene butadiene rubber (E-SBR), solution polymerized styrene butadiene rubber (S-SBR), and modified products thereof (modified S-SBR, modified E-SBR). Can be used. Examples of the modified SBR include modified SBR having a terminal and / or main chain modified, modified SBR coupled with tin, a silicon compound, or the like (condensate, one having a branched structure, or the like).

  The vinyl content of SBR is preferably 20% by mass or more, more preferably 25% by mass or more, from the viewpoint of sufficient wet grip performance and dry grip performance. The vinyl content is preferably 80% by mass or less, more preferably 70% by mass or less, from the viewpoint of good wear resistance. In addition, the vinyl content of SBR is a value measured by an infrared absorption spectrum analysis method.

  The styrene content of SBR is preferably 20% by mass or more, more preferably 25% by mass or more, from the viewpoint of sufficient wet grip performance and dry grip performance. Further, the styrene content is preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably from the viewpoint of good wear resistance and temperature dependency (state in which performance change with respect to temperature change is suppressed). Is 45 mass% or less.

  The glass transition point (Tg) of SBR is preferably −60 ° C. or higher, more preferably −50 ° C. or higher, from the viewpoint of good wet grip performance and dry grip performance. The Tg is preferably 0 ° C. or lower, more preferably −10 ° C. or lower, from the viewpoint of good initial grip performance and wear resistance.

  The content of SBR is 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and more preferably 90% by mass in 100% by mass of the rubber component from the viewpoint of sufficient heat resistance and wear resistance. % Or more, most preferably 100% by mass.

  The rubber component may contain other rubber components in addition to SBR. Examples of such other rubber components include natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Examples include diene rubbers, and non-diene rubbers such as ethylene propylene diene rubber (EPDM), butyl rubber (IIR), and halogenated butyl rubber (X-IIR). These other rubber components may be used alone or in combination of two or more.

<Filler>
The filler contains silica. This is because inclusion of silica can be expected to improve wet grip performance and fuel consumption characteristics. As silica, for example, dry method silica (anhydrous silica), wet method silica (hydrous silica) and the like can be used. Of these, wet-process silica is preferred because it has many silanol groups.

The silica used in the present invention has a CTAB (cetyltrimethylammonium bromide) specific surface area of 160 m ² / g or more and a BET specific surface area (N ₂ SA) by nitrogen adsorption of 170 m ² / g or more (hereinafter referred to as “fine particle silica”). Say). When such fine particle silica is used, deterioration of workability is particularly a concern. However, in the present invention, since an aluminum organic compound is used in combination, filler dispersibility is improved as described later, that is, an advantage of silica blending, Thus, it becomes possible to sufficiently bring out the improvement in fuel consumption characteristics and the improvement in wear resistance accompanying the improvement in reinforcement.

The CTAB specific surface area of the fine particle silica is preferably 165 m ² / g or more, more preferably 170 m ² / g or more, more preferably 180 m ² / g or more, more preferably 190 m ² / g or more, more preferably 195 m ² / g. More preferably, it is 197 m ² / g or more. On the other hand, the CTAB specific surface area is preferably 600 m ² / g or less, more preferably 300 m ² / g or less, and still more preferably 250 m ² / g or less from the viewpoint of securing good dispersibility and suppressing aggregation. The CTAB specific surface area is measured according to ASTM D3765-92.

The BET specific surface area (N ₂ SA) of the fine particle silica is preferably 175 m ² / g or more, more preferably 180 m ² / g or more, more preferably 190 m ² / g or more, more preferably 195 m ² / g or more, more preferably. Is 200 m ² / g or more, more preferably 210 m ² / g or more. On the other hand, the BET specific surface area is preferably 600 m ² / g or less, more preferably 300 m ² / g or less, and still more preferably 260 m ² / g or less, from the viewpoint of ensuring good dispersibility and suppressing aggregation. In addition, the BET specific surface area of a silica is measured according to ASTM D3037-81.

  The average primary particle diameter of the fine particle silica is preferably 20 nm or less, more preferably 17 nm or less, still more preferably 16 nm or less, and particularly preferably 15 nm or less. Although the minimum of this average primary particle diameter is not specifically limited, Preferably it is 3 nm or more, More preferably, it is 5 nm or more, More preferably, it is 7 nm or more. Although it has such a small average primary particle size, by aggregating it, a structure like carbon black can be formed, the dispersibility of silica can be further improved, and the reinforcement and wear resistance can be further improved. . The average primary particle diameter of the fine-particle silica can be obtained by observing with a transmission or scanning electron microscope, measuring 400 or more primary particles of silica observed in the visual field, and calculating the average.

  A specific kind of silica may be used alone, or two or more kinds may be used in combination. Such combinations also include combinations of particulate silica and other silicas.

  As fillers other than silica, any of those usually used in this field can be suitably used unless they are contrary to the object of the present invention. Examples of such fillers include carbon black. It is done. By adding carbon black, improvement in wear resistance can be expected. As a filler, what consists of a silica and carbon black is preferable.

  Examples of carbon black include carbon black produced by an oil furnace method, and two or more types having different colloidal characteristics may be used in combination. Specific examples include GPF, HAF, ISAF, and SAF.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 70 to 250 m ² / g, because it can provide good wet grip performance, dry grip performance and wear resistance, and 110 to 200 m ² / g. Is more preferable. Moreover, the dibutyl phthalate oil absorption (DBP) of carbon black is preferably 50 to 250 ml / 100 g for the same reason. Note that N ₂ SA of carbon black is a value measured according to JIS K 6217-2: 2001, and DBP is a value measured according to JIS K6217-4: 2001.

  As the carbon black, a specific type may be used alone, or two or more types may be used in combination.

  The compounding amount of silica is 50 parts by mass or more, more preferably 60 parts by mass or more, from the viewpoint of sufficient wet grip performance with respect to 100 parts by mass of the rubber component. On the other hand, the blending amount is 150 parts by mass or less, preferably 120 parts by mass or less, and more preferably 110 parts by mass or less, from the viewpoints of good dispersion and thus good wear resistance.

  The blending amount in the case of blending carbon black is preferably 5 parts by mass or more, more preferably 8 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoints of good wet grip performance, dry grip performance and wear resistance. That's it. On the other hand, from the viewpoint of maintaining good wet grip performance, the blending amount is preferably 50 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 20 parts by mass or less.

  The blending amount of the filler is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, more preferably 100 parts by mass with respect to 100 parts by mass of the rubber component, from the viewpoint of good wet grip performance, dry grip performance and wear resistance. Is 65 parts by mass or more. On the other hand, the blending amount is 170 parts by mass or less, more preferably 150 parts by mass or less, and still more preferably 120 parts by mass or less, from the viewpoint of good wet grip performance and wear resistance. The proportion of silica in the entire filler is preferably 70% by mass or more, more preferably 75% by mass or more, and more preferably 80% by mass or more from the viewpoint of satisfactorily exerting the effects of the present invention. . On the other hand, the ratio is 95% by mass or less, more preferably 90% by mass or less, for the same reason.

  When the filler consists only of silica and carbon black, the amount of carbon black may be determined from the above-mentioned “total amount of filler” and “the amount of silica”, or The blending amount of silica may be determined from the “total amount” and “the blending amount of carbon black”.

<Silane coupling agent>
The silane coupling agent is not particularly limited, and any of those usually used in this field can be suitably used. Examples of such silane coupling agents include bis (3-triethoxysilylpropyl) polysulfide, bis (2-triethoxysilylethyl) polysulfide, bis (3-trimethoxysilylpropyl) polysulfide, and bis (2-triethoxy). Methoxysilylethyl) polysulfide, bis (4-triethoxysilylbutyl) polysulfide, bis (4-trimethoxysilylbutyl) polysulfide and the like. Of these, bis (3-triethoxysilylpropyl) polysulfide and bis (2-triethoxysilylethyl) polysulfide are preferable, and bis (3-triethoxysilylpropyl) tetrasulfide and bis (2-triethoxysilylethyl) tetrasulfide are preferable. Is more preferable.

  The blending amount of the silane coupling agent is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of silica from the viewpoint of good wear resistance. , Preferably 5 parts by mass or more, more preferably 7 parts by mass or more. On the other hand, the blending amount is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and more preferably 12 parts by mass or less from the viewpoint of obtaining an improvement effect commensurate with an increase in cost.

  A specific kind of silane coupling agent may be used alone, or two or more kinds may be used in combination.

<Aluminum organic compounds>
An aluminum organic compound is a complex composed of aluminum and an organic compound, and generates aluminum hydroxide by a hydrolysis reaction. Accordingly, when such an aluminum organic compound is blended, at least a part of the aluminum organic compound undergoes hydrolysis during kneading to produce aluminum hydroxide.

As such an aluminum organic compound, for example, the formula (1):
Al (OR ^a ) (OR ^b ) (OR ^c ) ₃ (1)
(In the formula, R ^a , R ^b and R ^c each independently represents an aliphatic hydrocarbon group.)
The aluminum alcoholate shown by these is mentioned. Here, the aliphatic hydrocarbon group has a branched or unbranched alkyl group, alkenyl group or alkynyl group as a skeleton, and may contain a hetero atom such as an oxygen atom or a nitrogen atom. The aliphatic hydrocarbon group has 1 to 12 (C _1-12 ) carbon atoms (however, when the alkenyl group or alkynyl group is used as the skeleton, the lower limit of the carbon number is required to be at least 2.) The same is preferred), more preferably C _1-10, more preferably C _1-8, more preferably C _2-6 . Examples of the aliphatic hydrocarbon group represented by R ^a , R ^b or R ^c include an ethyl group (C ₂ ), an isopropyl group (C ₃ ), a secondary butyl group (C ₄ ), 3-ethoxycarbonyl-2- And propen-2-yl group (C ₆ ).

  Examples of the aluminum alcoholate include aluminum ethylate, aluminum isopropylate, aluminum diisopropylate mono-secondary butyrate, aluminum secondary butyrate, aluminum ethyl acetoacetate diisopropylate, and aluminum trisethyl acetoacetate.

  The compounding amount of the aluminum organic compound is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, more preferably 10 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of good wet grip performance and wear resistance. More than a part. On the other hand, the blending amount is preferably 45 parts by mass or less, more preferably 40 parts by mass or less, for the same reason.

  As the aluminum organic compound, a specific type of compound may be used alone, or two or more types may be used in combination.

  In addition to the components described above, the rubber composition of the present invention includes vulcanizing agents commonly used in the tire industry, such as softeners, anti-aging agents, waxes, stearic acid, zinc oxide, and sulfur. An agent, a vulcanization accelerator, and the like can be appropriately blended.

  Addition of the softener can be expected to improve wet grip performance, dry grip performance, initial grip performance, and the like. Although it does not specifically limit as a softener, Oil etc. are mentioned. Examples of the oil include process oils such as paraffinic, aroma-based, and naphthenic process oils. The blending amount in the case of blending oil is preferably 20 parts by mass or more, and more preferably 25 parts by mass or more with respect to 100 parts by mass of the rubber component, from the viewpoint of sufficiently obtaining the effect of addition. Further, the content is preferably 70 parts by mass or less, more preferably 60 parts by mass or less from the viewpoint of maintaining wear resistance. In the present specification, the oil content includes the amount of oil contained in the oil-extended rubber.

  A specific kind of softening agent may be used alone, or two or more kinds may be used in combination.

  Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, and guanidine vulcanization accelerators. Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide, N, N-dicyclohexyl-2-benzothiazylsulfenamide, and N-tert-butyl-2-benzo. And thiazylsulfenamide. Examples of the thiazole vulcanization accelerator include 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and the like. Examples of the thiuram vulcanization accelerator include tetramethylthiuram monosulfide, tetrabenzylthiuram disulfide, tetrakis (2-ethylhexyl) thiuram disulfide and the like. Examples of the guanidine vulcanization accelerator include diphenylguanidine.

  The content when blending the vulcanization accelerator is preferably 1 part by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of the rubber component from the viewpoint of achieving sufficient vulcanization. The content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, from the viewpoint of securing a sufficient scorch time.

  A specific kind of vulcanization accelerator may be used alone, or two or more kinds may be used in combination.

  The rubber composition of the present invention is produced by a general method. That is, it can be produced by a method of kneading the above components with a Banbury mixer, a kneader, an open roll or the like, and then vulcanizing if necessary.

<Application>
The rubber composition of the present invention can be used for various applications by taking advantage of its characteristics, and among them, it can be used as a rubber composition for tires. When the rubber composition of the present invention is used as a rubber composition for a tire, it can be used for various members constituting the tire, for example, a tread including a base tread, an inner liner, a sidewall, etc. It is preferably used for a tread (tire tread).

  When using the rubber composition of this invention for a tire, a tire can be manufactured from the rubber composition of this invention by a normal method. That is, if necessary, a mixture containing the above ingredients is kneaded, extruded in accordance with the shape of each member of the tire at an unvulcanized stage, and molded on a tire molding machine by a normal method. Thus, an unvulcanized tire is formed. A tire can be obtained by heating and pressurizing the unvulcanized tire in a vulcanizer, and air can be put into the tire to obtain a pneumatic tire.

  Although not intended to be bound by theory, the effect of using an aluminum organic compound instead of aluminum hydroxide is considered as follows. That is, although aluminum hydroxide contributes to the improvement of wet grip performance, it is inevitable that the wear resistance is deteriorated because the particle diameter is relatively large and there is no bonding point with rubber. The wear resistance can be expected to be improved to some extent by reducing the particle diameter, but there is a problem that the elongation of wet grip performance is reduced. However, the aluminum organic compound is a compound that generates aluminum hydroxide by hydrolysis, and the hydrolysis mode is the same as that of the silane coupling agent. Therefore, in cooperation with the silane coupling agent, moisture on the filler surface is consumed with high efficiency, and the share during kneading increases. As a result, kneading deepens and filler dispersibility is considered to be improved. Moreover, it is thought that an aluminum organic compound improves abrasion resistance by reacting with rubber | gum similarly to reaction of a silane coupling agent, and the reinforcement effect increasing.

  Improvement of filler dispersibility by blending an aluminum organic compound as described above also contributes to improving the deterioration of workability that is a concern when blending silica. This is especially true when so-called fine particle silica having a small particle diameter is used. For this reason, by using silica, especially fine particle silica, in combination with the aluminum organic compound, it is possible to sufficiently bring out the advantages of silica blending, that is, improvement in fuel consumption characteristics and improvement in wear resistance accompanying improvement in reinforcement. .

  The present invention will be described based on examples, but the present invention is not limited to the examples.

  The various chemicals used in the present specification are collectively shown below. Various chemicals were purified according to conventional methods as needed.

<Various chemicals used in the production of rubber composition>
S-SBR: Buna VSL 2525-0 manufactured by LANXESS (solution polymerization SBR, amount of bound styrene: 25% by mass, vinyl content: 25% by mass, Tg = −49 ° C.)
Silica A: ULTRASIL VN3 (CTAB specific surface area: 165 m ² / g) manufactured by EVONIK (N ₂ SA: 175 m ² / g)
Silica B: Zeolsil HRS1200MP (CTAB specific surface area: 195 m ² / g) (SOLVY) (N ₂ SA: 200 m ² / g)
Silica C: Zeosil Premium 200MP manufactured by SOLVAY (CTAB specific surface area: 200 m ² / g) (N ₂ SA: 220 m ² / g)
Silica D: Zeosil 1115MP (CTAB specific surface area: 105 m ² / g) (SOLVAY) (N ₂ SA: 115 m ² / g)
Carbon black: N220 manufactured by Mitsubishi Chemical Corporation (N ₂ SA: 114 m ² / g)
Aluminum hydroxide: Heidilite H-43 (trade name) manufactured by Showa Denko KK (average primary particle size: 0.75 μm)
Aluminum organic compound: Aluminum isopropylate (compound name) PADM (trade name) manufactured by Kawaken Fine Chemical Co., Ltd.
Oil: TDAE manufactured by Japan Energy Co., Ltd.
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Evonik Degussa
Anti-aging agent: NOCRACK 6C (N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine) (6PPD) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Wax: Ozoace 0355 manufactured by Nippon Seiwa Co., Ltd.
Stearic acid: Beads manufactured by NOF Corporation Zinc stearate zinc oxide: Two types of zinc oxide vulcanization accelerator manufactured by Mitsui Mining & Smelting Co., Ltd .: Noxeller NS manufactured by Ouchi Shinsei Chemical Co., Ltd.
Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd.

<Manufacture of rubber composition for tire>
In accordance with the formulation shown in Table 1, materials other than sulfur and a vulcanization accelerator were kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel Co., Ltd. Obtained. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 5 minutes under the condition of 80 ° C. using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized with a 2 mm thick mold at 170 ° C. for 20 minutes to obtain a vulcanized rubber composition. Further, the obtained unvulcanized rubber composition is molded into a tread shape and bonded together with other tire members on a tire molding machine to form an unvulcanized tire, which is vulcanized at 170 ° C. for 12 minutes, and tested. Tires (size: 195 / 65R15) were manufactured.

<Evaluation>
(Coupling agent unreacted rate index)
The unvulcanized rubber composition was cut into small pieces and extracted in ethanol for 24 hours. The amount of unreacted coupling agent extracted in the extract was measured by gas chromatography, and the ratio (mass%) of the unreacted coupling agent was calculated from the amount of coupling agent blended. The coupling agent unreacted rate index of the reference comparative example was set to 100, and the coupling agent unreacted rate of each formulation was indicated by an index by the following calculation formula. The lower the proportion of unreacted coupling agent and the lower the coupling agent unreacted rate index, the less unreacted coupling agent present in the unvulcanized rubber composition after the kneading step. means. That is, it means that more coupling agents reacted during the kneading process, indicating that it is good.

(Coupling agent unreacted ratio index) = (ratio of unreacted coupling agent amount of each formulation) / (ratio of unreacted coupling agent amount of reference comparative example) × 100

(Wet grip index)
In accordance with a known measurement method using a dynamic friction tester (DF tester) manufactured by Nippon Sangyo Co., Ltd., a test piece is cut out from the vulcanized rubber composition obtained above, and water is slowly sprinkled on the test piece. After confirming that a water film was formed, the dynamic friction coefficient (μ) was measured while increasing the linear velocity of the test specimen to 7 km / h. The wet grip index of the reference comparative example was set to 100, and the dynamic friction coefficient (μ) of each formulation was displayed as an index according to the following calculation formula. The larger the dynamic friction coefficient (μ) and the larger the wet grip index, the higher the wet grip performance and the higher the safety in running.

(Wet grip index) = (μ of each formulation) ÷ (μ of reference comparative example) × 100

(Low fuel consumption index)
A test piece was cut out from each vulcanized rubber composition and vulcanized rubber at 70 ° C. under conditions of initial strain 10%, dynamic strain 1%, frequency 10 Hz, using a viscoelastic spectrometer manufactured by Ueshima Seisakusho Co., Ltd. The loss tangent (tan δ) of the sheet was measured, the fuel efficiency index of the reference comparative example was taken as 100, and the tan δ of each formulation was displayed as an index according to the following calculation formula. The lower the value of tan δ and the higher the fuel efficiency index, the better the fuel efficiency.

(Low fuel efficiency index) = (tan δ of reference comparative example) ÷ (tan δ of each formulation) × 100

(Rubber breaking strength index)
The obtained vulcanized rubber composition was subjected to a tensile test using a No. 3 dumbbell according to JIS K6251 and measured for breaking strength (TB) and elongation at break (EB) (%). The numerical value of TB × EB / 2 was used as the breaking strength, and the breaking strength of each formulation was indicated by an index according to the following calculation formula with the breaking strength of the reference comparative example being 100. The larger the index, the better the breaking strength.

(Fracture strength index) = (TB of each formulation × EB / 2) ÷ (TB of reference comparative example × EB / 2) × 100

(Abrasion resistance index)
The amount of wear of the vulcanized rubber composition was measured under the conditions of room temperature, applied load of 1.0 kgf, and slip rate of 30% using a Lambourn type wear tester. With the wear resistance index of the reference comparative example as 100, the wear amount of each formulation was displayed as an index according to the following calculation formula. The smaller the amount of wear and the larger the wear resistance index, the better the wear resistance.

(Abrasion resistance index) = (Abrasion amount of reference comparative example) ÷ (Abrasion amount of each compound) × 100

(result)
The results are shown in Table 1.

Claims (7)

Rubber component containing styrene butadiene rubber, raw material chemicals containing CTAB specific surface area of 100 m ² / g or more and silica containing BET specific surface area by nitrogen adsorption of 110 m ² / g or more, silane coupling agent, and aluminum organic compound A rubber composition obtained by blending. The rubber composition according to claim 1, wherein the filler further contains carbon black. The blending amount of silica is 50 to 150 parts by weight, the blending amount of carbon black is 5 to 50 parts by weight, the blending amount of the aluminum organic compound is 5 to 45 parts by weight with respect to 100 parts by weight of the rubber component, and 100 parts by weight of silica. The rubber composition of Claim 2 whose compounding quantity of a silane coupling agent is 1-20 mass parts with respect to a part. The rubber composition according to any one of claims 1 to 3, wherein the silica has a CTAB specific surface area of 180 m ² / g or more and a BET specific surface area by nitrogen adsorption of 185 m ² / g or more. The aluminum organic compound has the formula (1):
Al (OR ^a ) (OR ^b ) (OR ^c ) ₃ (1)
(In the formula, R ^a , R ^b and R ^c each independently represents an aliphatic hydrocarbon group.)
The rubber composition of any one of Claims 1-4 which is an aluminum alkoxide shown by these. A tire tread produced using the rubber composition according to any one of claims 1 to 5. A tire having the tire tread of claim 6.